Plug cut-out



(No Model.)

F. S. RICHMOND. PLUG GUT-OUT.

No. 595,970. Patented Dec. 21 1897.

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I EQOZQT/C Ric/mama UNITED STATES PATENT Orrrcn.

FREDERIC S. RICHMOND, OF CHICAGO, ILLINOIS.

PLUG CUT-OUT.

SPECIFICATION forming part of Letters Patent No. 595,970, dated December 21, 1897.

Application filed January 8, 1897. Serial No. 618,444. (No model.)

To aZZ whom, it may concern:

Be it known that I, FREDERIO S. RICHMOND, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illi nois, have invented a certain new and useful Improvement in Plug Cut-Outs, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings,forming a part of this specification.

My invention relates to a plug cut-out for electrical circuits, my object being to provide an improved form of plug containing a fusible conductor or other cut-out, the arrangement of the parts being such that the plug maybe readily placed in and removed from the socket, while the oppositely-charged contactterminals are thoroughly separated and isolated when the plug rests in the socket.

My invention comprises a plug containing the cut-out and provided with a shouldered portion against which rests one of the contacts, an insulating body portion being provided which extends beyond the shouldered portion and carries upon its end the second contact-terminal. IVhen placed in the socket, the terminal on the shouldered portion of the plug engages a terminal mounted on the front of the base-plate containing the socket, while the end contact engages a contact-terminal in the bottom of the socket and mechanically holds the plug in place, the extending insulating body portion of the plug restingin the socket and thoroughly separating and isolating the oppositely-charged terminals.

In the accompanying drawings, Figure 1 is a top view of the plug, the cover being removed. Fig. 2 is a sectional view of the plug, showing the cover detached. Fig. 3 is a sectional view of the base upon which the socket is provided. Fig. 4: is a plan view of the base.

Like letters refer to like parts in the several figures.

The plug a is formed of porcelain or other insulating material and is provided in the end with a contact Z), having a square head Z), which fits in a recess upon theinterior of the plug to prevent the turning of the contact. The end of the contact is threaded, and a locking-nut Z) screws upon the same and against the end of the plug to lock the contact in position. The plug is provided with a shouldered portion a, against which is secured a ringc by means of screws 0 c passing through the shoulder a and screwing into the ring. The contact Z) and the ring 0 constitute the terminals of the plug and are electrically connected by the fusible conductor d, the ends of which are soldered or otherwise attached to the screws 0 and the head of the contact Z). In the side wall of the socket is an oblique vent e. A cover f fits overthe end of the plug and carries upon the interior wall of the flange a pair of lugs f f, which when the cover is partially rotated engage the under faces of the projections a a to hold the cover in position.

The base preferably comprises two plates g g, of slate or other insulating and non-combustible material, between which is clamped the bar or contact h, situated opposite the opening or socket 7t, provided in the plate g. A hole 71 is tapped in the contact bar or plate h to receive the end of the plugcontact Z). Upon the front face of the plate g is a ring Z, with which the ring 0 on the plug makes contact when the plug is in the socket. The ring Zcarries an arm Z, through which passes a bolt in to secure the ring to the face of the plate g. A washer m fits over the end of the bolt,and a nutm screws upon the end,whereby the terminal wire may be clamped between the washer and the arm Z. The rings 0 and Z may be formed in one or several pieces and constitute a whole or a partial circle.

lVhen the plug is in position in the socket, the contact Z) is screwed into the tapped hole in the contact-plate h, thus completing the electrical connection between the contact Z) and the contact 71. The screwing of the contact Z) into the contact h draws the ring 0 of the plug into contact with the ring Z, thus completing the circuit between the contacts IL and Zof the socket through the fuse-wire (Z of the plug. The contacts of the socket being upon opposite sides of the insulating-plate 9 there is little danger of short-circuiting the same, and the contacts on the plug being separated by a considerable distance danger of crossing these contacts also is avoided. A construction is thus provided which effectively removes the danger of accidental short-cireuiting incident upon the employment of the cut-out plugs of the prior art.

When the fuse is blown, the molten metal, it forced through the vent e, strikes the insulatin g and non-combustible wall of the socket and is thus prevented from doin any injury.

In order that it may be impossible to place a plug having a fusible conductor of a higher capacity on a circuit designed for a smaller current, I have found it desirable in some instances to make the plugs so that those of different capacities will not be interchangeable, so that a plug of, say, ten amperes cannot be placed on a circuit designed for a maximum current of, say, five am peres. This non-interchangeability may be secured by providing threads of different pitch upon the contacts of the plugs or by forming the contacts with dif ferent diameters, whereby a plug of one capacity cannot be placed in a socket designed for a plug of a different capacity.

Having described m y invention, what I claim as new, and desire to secure by Letters Patent, is

1. The combination with a base-plate provided with an opening or socket, of a contactterminal in the bottom of said socket, a terminal resting against the front face of said baseplate, a plug carrying the cut-out and provided with a shouldered portion at one end andL with an insulating body portion extending beyond said shouldered portion and adapted to fit Within said opening or socket, a ring mounted upon said shouldered portion and adapted to engage the contact-terminal on the face of the base-plate, and a contact provided in the end of said projecting body adapted to engage the contact in the bottom of said socket mechanically as well as electrically to hold the plug in place, whereby the projecting insulatingbody of the plug rests in the opening or socket to separate and isolate the op positely-charged terminals, substantially as described.

2. The combination with a base-plate provided with an opening or socket, of a contactterminal situated in the bottom of said socket and provided with a tapped hole, a terminal in the form of a ring mounted upon the front face of said base-plate and surrounding said opening or socket, a plug inclosing the cutout and provided at the end with a removable cap or cover and carrying a shouldered portion near the end supporting the cap, and provided with an insulating body portion extending beyond said shouldered portion and adapted to fit within said opening or socket, a ring mounted upon said shouldered portion and adapted to engage the ring on the face of the base-plate, an d a threaded contact-terminal mounted upon the end of said projecting body adapted to engage the tapped hole in the terminal situated in the bottom of the socket, whereby the projecting insulating-bod y of the plug rests in the opening or socketto separate and isolate the oppositely-charged terminals, substantially as described.

3. In a cut-out plug, the combination with an insulating-body carrying the cut-out, said plug being provided with a shouldered portion and with an insulating body portion extending beyond said shouldered portion, of a terminal mounted against the face of said shouldered portion, and a threaded terminal mounted upon the end of said extending body portion, substantially as described.

4. In a cut-out plug, the combination with the insulating hollow body provided with a shouldered portion a and a body portion a extending beyond the same, of a cover f fitting upon said hollow body and inclosing the cut-out, a threaded contact Z) passing through the end of said body portion a, and a ring 0 resting against said shouldered portion a,substantially as described.

5. In a cut-out plug, the combination with the body a, of the threaded contact 11 passing through the end thereof and provided with a square head fitting in a recess in said body, the lock-nut b the ring 0 resting against a shoulder on the body of the plug, the screws passing through said shoulder and engaging said ring, and the cover fitting upon said body, substantially as described.

(5. In a cut-out plug, the combination with the insulating-body provided with a shouldered portion a and a body portion a extending beyond the same, and adapted to lit in the plug-socket, a threaded contact mounted upon the end of said body portion, a ring-contact resting against said shouldered portion, and a fuse-wire carried by the plug and connected between said ring-contact and said threaded contact, substantially as described.

7. In combination, a base-plate provided with an opening or socket, a contact-terminal in the bottom thereof having a tapped hole, a ring-terminal mounted on the face of said base-plate, a plug carrying the cut-out having a shoulder at one end and an insulating body portion extending beyond the same and adapted to fit in said socket, a threaded contact on the end of said body portion engaging the tapped hole of the socket and a ring-contact on said shoulder engaging the ring-contact of the socket, substantially as described.

In witness whereof I havehereunto subscribed my name in the presence of two witnesses.

FREDERIG RICHMOND.

W'itnesses:

L. K. Consrocn, W. CLYDE Jesus. 

